Is a page where the print is too small to read functional

Dear LVTF,
I was trying to get at the concept:  text that is too small is not
functional. This is a well defined concept scientifically. There is a
*fluent* range of font size. Inside this range people read at max speed and
don't make many mistakes. When font size is smaller, even by a little, then
people cannot read effectively. Their speed drops dramatically and they
make too many mistakes to read with fluency.

People with full sight rarely experience this, because publications that
use font that is smaller than the fluent range don't survive. Legge and
Bigelow collected typographic data from the time of Gutenberg to the
present day to verify this fact. Small print publications don't survive
because their font is not functional for reading.

People with full sight do experience this with text for legal disclaimers.
These are made deliberately small so that people will not read them --
deliberate dysfunctionality.

So, should font smaller than the fluent range be deemed as not functional.
That would cause the page to fail.

Best, Wayne